Charged black hole Solutions with Toroidal horizons in f(R)-gravity surrounded by Quintessence and Cloud of Strings: Effective Potential Barrier, Quasinormal Modes

Author(s):  
Younes Younesizadeh ◽  
Ehsan Gholami ◽  
Zahra Mohammaddoust Lashkami
2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Andres Anabalon ◽  
Dumitru Astefanesei ◽  
Antonio Gallerati ◽  
Mario Trigiante

Abstract In this article we study a family of four-dimensional, $$ \mathcal{N} $$ N = 2 supergravity theories that interpolates between all the single dilaton truncations of the SO(8) gauged $$ \mathcal{N} $$ N = 8 supergravity. In this infinitely many theories characterized by two real numbers — the interpolation parameter and the dyonic “angle” of the gauging — we construct non-extremal electrically or magnetically charged black hole solutions and their supersymmetric limits. All the supersymmetric black holes have non-singular horizons with spherical, hyperbolic or planar topology. Some of these supersymmetric and non-extremal black holes are new examples in the $$ \mathcal{N} $$ N = 8 theory that do not belong to the STU model. We compute the asymptotic charges, thermodynamics and boundary conditions of these black holes and show that all of them, except one, introduce a triple trace deformation in the dual theory.


2020 ◽  
Vol 80 (7) ◽  
Author(s):  
Tong-Tong Hu ◽  
Shuo Sun ◽  
Hong-Bo Li ◽  
Yong-Qiang Wang

Abstract Motivated by the recent studies of the novel asymptotically global $$\hbox {AdS}_4$$AdS4 black hole with deformed horizon, we consider the action of Einstein–Maxwell gravity in AdS spacetime and construct the charged deforming AdS black holes with differential boundary. In contrast to deforming black hole without charge, there exists at least one value of horizon for an arbitrary temperature. The extremum of temperature is determined by charge q and divides the range of temperature into several parts. Moreover, we use an isometric embedding in the three-dimensional space to investigate the horizon geometry. The entropy and quasinormal modes of deforming charged AdS black hole are also studied in this paper. Due to the existence of charge q, the phase diagram of entropy is more complicated. We consider two cases of solutions: (1) fixing the chemical potential $$\mu $$μ; (2) changing the value of $$\mu $$μ according to the values of horizon radius and charge. In the first case, it is interesting to find there exist two families of black hole solutions with different horizon radii for a fixed temperature, but these two black holes have same horizon geometry and entropy. The second case ensures that deforming charged AdS black hole solutions can reduce to standard RN–AdS black holes.


2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Ángel Rincón ◽  
Victor Santos

AbstractIn this work, we investigate the quasinormal frequencies of a class of regular black hole solutions which generalize Bardeen and Hayward spacetimes. In particular, we analyze scalar, vector and gravitational perturbations of the black hole with the semianalytic WKB method. We analyze in detail the behaviour of the spectrum depending on the parameter p/q of the black hole, the quantum number of angular momentum and the s number. In addition, we compare our results with the classical solution valid for $$p = q = 1$$ p = q = 1 .


2020 ◽  
Vol 35 (27) ◽  
pp. 2050172
Author(s):  
Younes Younesizadeh ◽  
Ali Hassan Ahmed ◽  
Amir A. Ahmad ◽  
Feyzollah Younesizadeh ◽  
Morad Ebrahimkhas

In this work, a new class of black hole solutions in dilaton gravity has been obtained where the dilaton field is coupled with nonlinear Maxwell invariant as a source. The background space–time in this works is considered as the [Formula: see text]-dimensional toroidal metric. In the presence of the dilaton field (for some unique values of [Formula: see text][Formula: see text] a ), the electric field increases as we got farther away from the origin. In the absence of the dilaton field [Formula: see text], the electric field always decreases as one goes farther away from the origin. In the thermodynamical analysis, we obtain the Smarr formula for our solution. We find that the presence of the dilaton field makes the solutions to be locally stable near the origin. Also, this field vanishes the global stability near the origin compared to the no dilaton field case [Formula: see text]. We can say that the dilaton field has a crucial impact on the thermodynamical stability and it is a key factor in stability analysis. We study the quasinormal modes (QNMs) of black hole solutions in dilaton gravity. For this purpose, we use the WKB approximation method upto first order corrections. We have shown the perturbations decay in corresponding diagrams when the dilaton parameter [Formula: see text] and coupling constant [Formula: see text] change. Motivated by the thermodynamical analogy of black holes and Van der Waals liquid/gas systems, in this work, we investigate PV criticality of the obtained solution. We extend the phase space by considering the cosmological constant as thermodynamic pressure. We obtain the equation of state (EOS) and plot the relevant PV [Formula: see text] diagrams. We also present a class of interior solutions corresponding to the exterior solution in dilaton gravity. The solution which is obtained for a linear equation of state is regular and well-behaved at the stellar interior. a Dilaton field representation.


2010 ◽  
Vol 81 (10) ◽  
Author(s):  
Shao-Wen Wei ◽  
Yu-Xiao Liu ◽  
Ke Yang ◽  
Yuan Zhong

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
Zi-Yu Tang ◽  
Bin Wang ◽  
Eleftherios Papantonopoulos

AbstractWe consider Maxwell-f(R) gravity and obtain an exact charged black hole solution with dynamic curvature in D-dimensions. Considering a spherically symmetric metric ansatz and without specifying the form of f(R) we find a general black hole solution in D-dimensions. This general black hole solution can reduce to the Reissner–Nordström (RN) black hole in D-dimensions in Einstein gravity and to the known charged black hole solutions with constant curvature in f(R) gravity. Restricting the parameters of the general solution we get polynomial solutions which reveal novel properties when compared to RN black holes. Specifically we study the solution in $$(3+1)$$ ( 3 + 1 ) -dimensions in which the form of f(R) can be solved explicitly giving a dynamic curvature and compare it with the RN black hole. We also carry out a detailed study of its thermodynamics.


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